Terahertz detector and method based on N×M dielectric resonant antenna array

ABSTRACT

The present disclosure discloses a terahertz detector based on a N×M dielectric resonant antenna array, wherein a N×M on-chip dielectric resonant terahertz antenna array is connected to a matching network, the matching network is connected to a source of a NMOSFET, a gate of the NMOSFET is sequentially connected to a first bias resistor and a first bias voltage, a third transmission line is connected between the first bias resistor and the gate, a drain of the NMOSFET is connected to a first DC blocking capacitor, the other end of the first DC blocking capacitor is connected to a low noise preamplifier, a second bias resistor and a second bias voltage are further connected between the first DC blocking capacitor and the low noise preamplifier, and the low noise preamplifier is further provided with a voltage feedback loop. The present disclosure also discloses a design method for the same.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority to Chinese Patent Application No.201811582676.0 filed on Dec. 24, 2018. The content of the aforementionedapplication, including any intervening amendments thereto, areincorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to the field of terahertz technology, andin particular to a terahertz detector and method based on a N×Mdielectric resonant antenna array.

BACKGROUND

THz radiation (T-ray) generally refers to an electromagnetic wave havinga frequency in the range of 0.1 THz to 10 THz (wavelength in the rangeof 30 μm to 3 mm), and its long wavelength-band direction coincides withthe millimeter wave (sub-millimeter wave), and its short wavelength-banddirection coincides with the infrared ray. Therefore, it belongs to thefar infrared wave band.

Since the THz wave is in the position of a special electromagneticspectrum, it has many superior characteristics and has great scientificsignificance. It mainly embodies in the following aspects. Firstly, itsquantum energy and blackbody temperature are very low. Since the photonenergy of the terahertz wave is very low, it is not easily ionized whenit penetrates a substance, and thus it can be used for safenon-destructive detection. Secondly, many substance macromolecules, suchas biomacromolecules, have vibration and rotational frequencies in theTHz wave band, so they exhibit strong absorption and resonance in theTHz wave band. For example, many explosives have “terahertzfingerprinting” characteristics, which allow them to be identified fromclothing and when mixed with other materials, such as the detection ofnarcotics/drugs. The strongly permeable THz wave can penetratesubstances such as ceramics, fat, carbon sheets, cloth, plastics and thelike with little attenuation. Therefore, it can be used to detect avariety of low-concentration polarized gases, and is suitable forspecial fields such as environmental protection and military chemicalreconnaissance. Thirdly, the advantages of applying the terahertztechnology in environmental monitoring, protection, national securityand anti-terrorism, and so forth, can make up for the shortcomings ofthe infrared technology and microwave technology. In addition, theterahertz wave is in the blank area between the microwave millimeterwave and the infrared wave band and between the electronics and thephotonics. It is also a blank area of human science and technology, andhas a very broad development space. Therefore, the active research workof THz science and technology is of strategic importance, and theterahertz detector, which is the basis of terahertz application, is acritical component of terahertz security and detection.

At present, terahertz detection based on N-typeMetal-Oxide-Semiconductor Field-Effect Transistor (NMOSFET) has provedto be very feasible, but due to Complementary Metal Oxide Semiconductor(CMOS) process limitations, the larger loss of conventional terahertzantennas such as on-chip dipoles and patches in terahertz detectorsleads to the narrower impedance matching bandwidth of the conventionalterahertz antenna such as on-chip dipoles and patches, which greatlyaffects the detection sensitivity of the terahertz detector. However,the current development trend of terahertz detectors is highsensitivity. Therefore, it is a hot research topic to develop an on-chipterahertz antenna with low loss and wide impedance matching bandwidthbased on the CMOS compatible technology to achieve high sensitivityterahertz detection.

The present disclosure innovatively introduces a N×M on-chip dielectricresonant terahertz antenna array into a NMOSFET-based terahertzdetector, and achieves higher gain and wider impedance matchingbandwidth for the on-chip terahertz antenna in comparison withconventional NMOSFET terahertz detectors based on terahertz antennassuch as on-chip dipoles and patches or a single on-chip dielectricresonant terahertz antenna.

SUMMARY

A main object of the present disclosure is to provide a NMOSFETterahertz detector and method based on a N×M dielectric resonant antennaarray, which is intended to reduce the loss of the on-chip terahertzantenna and improve the gain and radiation efficiency of the on-chipterahertz antenna, improving the detection sensitivity of the NMOSFETterahertz detector.

To achieve the above object, the present disclosure proposes a NMOSFETterahertz detector based on a N×M dielectric resonant antenna array,comprising a N×M on-chip dielectric resonant terahertz antenna array,wherein N is the number of rows in the array, M is the number of columnsin the array and the N and the M are positive integers, wherein the N×Mon-chip dielectric resonant terahertz antenna array is connected to amatching network, the matching network is connected to a source of aNMOSFET, a gate of the NMOSFET is sequentially connected to a first biasresistor and a first bias voltage, a transmission line is connectedbetween the first bias resistor and the gate, a drain of the NMOSFET isconnected to a first Direct Current (DC) blocking capacitor, the otherend of the first DC blocking capacitor is connected to a low noisepreamplifier, a second bias resistor and a second bias voltage arefurther connected between the first DC blocking capacitor and the lownoise preamplifier, and the low noise preamplifier is further providedwith a voltage feedback loop.

Preferably, the N×M on-chip dielectric resonant terahertz antenna arrayis an array structure consisting of N×M on-chip H-shaped slotstructures, each of the on-chip H-shaped slot structures is connected atthe surface with a rectangular dielectric resonator block through aninsulating adhesive layer, and a connection slot extending outwardly ofeach of the on-chip H-shaped slot structures is sequentially connectedto the connection slots of adjacent on-chip H-shaped slot structures andform a non-overlapping power division network ring, the power divisionnetwork ring being provided with two parallel antenna-sections connectedto the outside.

Preferably, when the N and the M are even, a connection port of theconnection slot of the uppermost on-chip H-shaped slot structure and aconnection port of the connection slot of the lowermost on-chip H-shapedslot structure have a phase difference of 180°.

Preferably, the on-chip H-shaped slot structures are formed on a surfaceof an integrated process top layer metal and is located within a metalcavity formed by stacking intermediate layer metals, other than theintegrated process top layer metal and an integrated process bottomlayer metal in an integrated process, and metal vias.

Preferably, the on-chip H-shaped slot structure comprises a leftvertical slot and a right vertical slot arranged in parallel, oppositesides of the left vertical slot and the right vertical slot areconnected to an inverted L-shaped left side slot and right side slot,respectively, a horizontal portion of the left side slot is connected inthe middle of the left vertical slot, a horizontal portion of the rightside slot is connected in the middle of the right vertical slot, andvertical portions of the left side slot and the right side slot areparallel to each other and constitute two lead-out slots for connectingthe antenna to an outside structure.

Preferably, the matching network comprises a first transmission lineconnected to the on-chip dielectric resonant terahertz antenna and thesource respectively at both ends, a middle portion of the firsttransmission line is connected to one end of a second transmission line,and the other end of the second transmission line is grounded.

Preferably, the voltage feedback loop comprises a first resistorconnected to two ends of the low noise preamplifier, a left end of thefirst resistor connected to a negative terminal of the low noisepreamplifier is sequentially connected to a second resistor, a second DCblocking capacitor and the ground, and a right end of the first resistoris also sequentially connected to a third DC blocking capacitor and theground.

The present disclosure further proposes a method of designing the N×Mon-chip dielectric resonant terahertz antenna array, wherein N is thenumber of rows in the array, M is the number of columns in the array andthe N and the M are positive integers, comprising steps of:

S1: with a resonance mode being in TE_(m,δ,n) mode, calculating 3Ddimensions of the rectangular dielectric resonator block by solving atranscendental equation, the transcendental equation being:

$\begin{matrix}{{k_{y}\mspace{14mu}{\tan\left( \frac{k_{y}W_{DRA}}{2} \right)}} = \sqrt{{\left( {ɛ_{r} - 1} \right)k_{mn}^{2}} - k_{y}^{2}}} & (1)\end{matrix}$where

$\begin{matrix}{{k_{mn} = \frac{2\pi\; f_{mn}}{c}},{k_{x} = {m\frac{\pi}{L_{DRA}}}},{k_{z} = {n\frac{\pi}{2H_{DRA}}}},{{k_{x}^{2} + k_{y}^{2} + k_{z}^{2}} = {ɛ_{r}k_{mn}^{2}}}} & (2)\end{matrix}$c is the speed of light, ε_(r) is a relative dielectric constant andf_(mn), is the operating frequency of the rectangular dielectricresonator block in this mode TE_(m,δ,n);

wherein m, n and δ are the number of electromagnetic waves generated inthe x, y, z directions, and are integers;

wherein k_(y) is the component of the propagation constant ofelectromagnetic waves in the medium in the y direction, and k_(mn) isthe propagation constant of electromagnetic waves in the medium, whereink_(x) and k_(z) are the components of the propagation constant in the xand z directions when electromagnetic waves propagate in the medium;

wherein W_(DRA) is the width of the medium in the x direction, L_(DRA)is the length of the medium in the y direction and, H_(DRA) is theheight of the medium in the z direction;

S2: in a process of designing an on-chip excitation structure, selectinga top layer metal Metal6 to design a H-shaped slot structure whileselecting a bottom layer metal Metal1 as a metal base plate, andstacking intermediate metal layers and metal vias to form a metalshielding cavity around the H-shaped slot structure;

S3: selecting a suitable insulating adhesive layer to combine therectangular dielectric resonator block and the on-chip H-shaped slotstructure;

S4: adopting a Grounded Coplanar Waveguide(GCPW) transmission linestructure composed of the top layer metal Metal6 and the bottom layermetal Metal1 to design a power division network, and then optimizingparameters by means of High Frequency Structure Simulator (HFSS)software so as to meet impedance matching and port phase requirements ofthe GCPW power division network;

S5: performing co-simulation and optimization of the GCPW power divisionnetwork with the N×M on-chip dielectric resonant terahertz antennaarray.

Preferably, in the S1, the resonance mode of the rectangular dielectricresonator block is selected to be TE_(1,δ,3) mode of high-order resonantmodes, and the transcendental equation is solved by programming withmathematical software Matlab, to obtain the 3D dimensions of therectangular dielectric resonator block at a frequency of 300 GHz beingW_(DR)=250 μm, L_(DR)=250 μm, H_(DR)=400 μm, respectively; in the S2,the dimensions of the H-shaped slot structure are I₁=70 μm, I₂=220 μm,w_(s)=9.5 μm, w₁=15 μm, w₂=10 μm, w₃=10 μm; and the insulating adhesivelayer mentioned in the step S3 is selected as a thermal stabilityinsulating adhesive having a relative dielectric constant of 2.4 and athickness of 10/m.

The technical solution according to the present disclosure has thefollowing advantages over the prior art.

The technical solution according to the present disclosure combines arectangular dielectric resonator block in TE_(1,δ,3) mode of high-ordermodes with low loss characteristics and an on-chip slot feed structure,so as to design a N×M on-chip dielectric resonant terahertz antennaarray, and the optimization of the impedance matching through a GCPWpower division network and the superposition of vibration sourceantennas in the space electromagnetic field can effectively overcome thetechnical problem of low gain and narrow impedance matching bandwidthfor the on-chip terahertz antenna existed when designing the on-chipterahertz antenna. Compared with the conventional NMOSFET terahertzdetectors based on terahertz antennas such as on-chip dipoles andpatches or a single on-chip dielectric resonant terahertz antenna, thetechnical solution of the present disclosure achieves higher gain andwider impedance matching bandwidth for the on-chip terahertz antenna,and improves the detection sensitivity of the NMOSFET terahertzdetector.

The output voltage signal of the NMOSFET terahertz detector of thetechnical solution according to the present disclosure is a DC voltagesignal, and the magnitude of the DC voltage signal is proportional tothe radiation intensity of the terahertz signal. The intensityinformation of the incident terahertz signal can be obtained accordingto the magnitude of the output voltage signal of the terahertz detector,thereby realizing terahertz detection, so that the technical problemthat the existing terahertz antenna has low gain and narrow impedancematching bandwidth for the on-chip terahertz antenna is effectivelysolved, ultimately achieving a terahertz detection with highsensitivity.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions inembodiments of the present disclosure or the prior art, the accompanyingdrawings needed to be used in the description of the embodiments or theprior art will be briefly described below. Obviously, the accompanyingdrawings in the following description are only some embodiments of thepresent disclosure, and other accompanying drawings can be obtained byordinary persons skilled in the art from the structures illustrated inthese accompanying drawings without any inventive efforts.

FIG. 1 is a schematic structural view of a NMOSFET terahertz detectorbased on a 2×2 dielectric resonant terahertz antenna array according toan embodiment of the present disclosure;

FIG. 2 is a schematic structural view of a 2×2 on-chip dielectricresonant terahertz antenna array according to an embodiment of thepresent disclosure;

FIG. 3 is a schematic structural view of an on-chip dielectric resonantterahertz antenna unit according to an embodiment of the presentdisclosure;

FIG. 4 is a schematic structural view of an on-chip H-shaped slotstructure according to an embodiment of the present disclosure;

FIG. 5 is a schematic structural view of a 4-way GCPW power divisionnetwork in FIG. 2;

FIG. 6 is a schematic structural view of a rectangular dielectricresonator block according to an embodiment of the present disclosure;

FIG. 7 is a graph showing the S parameter of a 4-way GCPW power divisionnetwork according to an embodiment of the present disclosure as afunction of frequency;

FIG. 8 is a graph showing the phases between ports of a 4-way GCPW powerdivision network according to an embodiment of the present disclosure asa function of frequency;

FIG. 9 is a graph showing the return loss S11 of a 2×2 on-chipdielectric resonant terahertz antenna array according to an embodimentof the present disclosure as a function of frequency;

FIG. 10 is a graph showing the gain of a 2×2 on-chip dielectric resonantterahertz antenna array according to an embodiment of the presentdisclosure as a function of frequency;

FIG. 11 is a radiation pattern of a 2×2 on-chip dielectric resonantterahertz antenna array according to an embodiment of the presentdisclosure.

DESCRIPTION OF THE REFERENCE NUMERALS

No. Name 1 First bias voltage 2 First bias resistor 3 NMOSFET 31 Source32 Drain 33 Gate 4 2 × 2 on-chip dielectric resonant terahertz antennaarray 41 First on-chip H-shaped slot structure 411 First left connectionslot 412 First right connection slot 413 Left vertical slot 414 Rightvertical slot 415 Left side slot 416 Right side slot 42 Second on-chipH-shaped slot structure 421 Second left connection slot 422 Second rightconnection slot 43 Third on-chip H-shaped slot structure 431 Third leftconnection slot 432 Third right connection slot 44 Fourth on-chipH-shaped slot structure 441 Fourth left connection slot 442 Fourth rightconnection slot 45 Top layer metal 46 Insulating adhesive layer 47Rectangular dielectric resonator block 48 Metal cavity 49 Bottom layermetal 5 Matching network 51 First transmission line 52 Secondtransmission line 6 First DC blocking capacitor 7 Second bias voltage 8Second bias resistor 9 Low noise preamplifier 10 First resistor 11Second resistor 12 Second DC blocking capacitor 13 Grounding 14 Third DCblocking capacitor 15 Third transmission line

The implementation, functional features and advantages of the presentdisclosure will be further described in the light of embodiments withreference to the accompanying drawings.

DETAILED DESCRIPTION

The technical solutions according to the embodiments of the presentdisclosure are clearly and completely described in the following withreference to the accompanying drawings of the embodiments of the presentdisclosure. Obviously, the described embodiments are only a part of theembodiments of the present disclosure, and not all the embodiments. Allother embodiments obtained by ordinary persons skilled in the art basedon the embodiments of the present disclosure without creative effortsare within the scope of the present disclosure.

It should be noted that if there is a directional indication (such asup, down, left, right, front, back, . . . ) mentioned in the embodimentsof the present disclosure, the directional indication is only used toexplain the relative positional relationship between components, motionstatus, and the like in a specific posture (as shown in the drawing),and if the specific posture changes, the directional indication alsochanges accordingly.

In addition, if there is a description of “first”, “second”, etc. in theembodiments of the present disclosure, the description of the “first”,“second”, etc. is used for the purpose of illustration only, and is notto be construed as an its relative importance or implicit indication ofthe number of technical features indicated. Thus, the features definedby “first” or “second” may include at least one of the features, eitherexplicitly or implicitly. In addition, the technical solutions among thevarious embodiments may be combined with each other, but must be basedon the enablement of those skilled in the art, and when the combinationof the technical solutions is contradictory or impossible to implement,it should be considered that such combination of technical solutionsdoes not exist, and is not within the scope of protection claimed by thepresent disclosure.

The present disclosure proposes a NMOSFET terahertz detector based on aN×M dielectric resonant antenna array and a design method for the N×Mon-chip dielectric resonant terahertz antenna array.

Referring to FIG. 1, a specific embodiment of the present disclosure isdescribed in detail by taking a NMOSFET terahertz detector based on a2×2 dielectric resonant antenna array as an example. The NMOSFETterahertz detector based on a 2×2 dielectric resonant antenna arraycomprises a 2×2 on-chip dielectric resonant terahertz antenna array 4.The 2×2 on-chip dielectric resonant terahertz antenna array 4 isconnected to a matching network 5, and further the matching network 5 isconnected to a source 31 of a NMOSFET 3. A gate 33 of the NMOSFET 3 issequentially connected to a first bias resistor 2 and a first biasvoltage 1. An open-end quarter-wavelength third transmission line 15 isconnected between the gate 33 and the first bias resistor 2. A drain 32of the NMOSFET 3 is connected to a first DC blocking capacitor 6, andthe other end of the first DC blocking capacitor 6 is connected to a lownoise preamplifier 9. A second bias resistor 8 is connected between thefirst DC blocking capacitor 6 and the low noise preamplifier 9, and theother end of the second bias resistor 8 is connected to the first biasvoltage 7 so as to provide a DC power supply to the low noisepreamplifier 9. In addition, the low noise preamplifier 9 is alsoconnected to a voltage feedback loop.

Referring to FIGS. 2 to 4, the 2×2 on-chip dielectric resonant terahertzantenna array 4 of the present embodiment is a 2×2 antenna array formedon a rectangular integrated process top layer metal 45. The 2×2 on-chipdielectric resonant terahertz antenna array 4 comprises four on-chipH-shaped slot structures 41, 42, 43 and 44 having the same structure,which are formed at four ends of the rectangular integrated process toplayer metal 45, respectively. The four on-chip H-shaped slot structures41, 42, 43 and 44 are connected to four rectangular dielectric resonatorblocks 47 having the same structure through insulating adhesive layers46, respectively. Herein, a first left connection slot 411 on the leftside of the first on-chip H-shaped slot structure 41 at the upper leftend portion is connected to a second left connection slot 421 on theleft side of the second on-chip H-shaped slot structure 42 at the lowerleft end portion, and a first right connection slot 412 on the rightside of the first on-chip H-shaped slot structure 41 is connected to athird left connection slot 431 on the left side of the third on-chipH-shaped slot structure 43 at the upper right end portion. A third rightconnection slot 432 on the right side of the third on-chip H-shaped slotstructure 43 is connected to a fourth right connection slot 442 on theright side of the fourth on-chip H-shaped slot structure 44 at the lowerright end portion. A second right connection slot 422 on the right sideof the second on-chip H-shaped slot structure 42 and a fourth leftconnection slot 441 on the left side of the fourth on-chip H-shaped slotstructure 44 extend outwardly and constitute a connection port forconnecting an external circuit of the antenna array. That is, theconnection slots extending outwardly of each of the on-chip H-shapedslot structures 41, 42, 43, 44 are sequentially connected with theconnection slots of its adjacent on-chip H-shaped slot structures toform a non-overlapping 4-way GCPW power division network ring. The powerdivision network ring is provided with two parallel antenna-sectionsconnected to the outside.

As shown in FIG. 2 and FIG. 5, N and M of the NMOSFET terahertz detectorbased on the N×M dielectric resonant antenna array of the technicalsolution of the present disclosure are both positive integers. When theN and the M are both even, a connection port of the connection slot ofthe uppermost on-chip H-shaped slot structure and a connection port ofthe connection slot of the lowermost on-chip H-shaped slot structurehave a phase difference of 180°. As shown in FIG. 5 of the embodiment,the phase differences between each of the connection port 4 and theconnection port 5, and any one of the connection port 1, the connectionport 2 and the connection port 3 are 180°, and the phase differences of180° are set to increase the antenna array gain in a fixed direction andimprove matching performance of the antenna.

Referring to FIG. 2 and FIG. 4, the four on-chip H-shaped slotstructures 41 having the same structure of the present embodimentcomprises a left vertical slot 413 and a right vertical slot 414 formedin parallel. Opposite sides of the left vertical slot 413 and the rightvertical slot 414 are formed with an inverted L-shaped left side slot415 and right side slot 416, respectively. The horizontal portions ofthe inverted L-shaped left side slot 415 and right side slot 416 areconnected in the middle of the left vertical slot 413 and the rightvertical slot 414, and the vertical portion of the inverted L-shapedleft side slot 415 is connected to the first left connection slot 411.The specific structures of the on-chip H-shaped slot structures 41, 42,43 and 44 are shown in FIG. 2, and detailed description thereabout isomitted herein.

Referring to FIG. 4, additionally, the on-chip H-shaped slot structures41, 42, 43 and 44 of the present embodiment are formed on a surface ofthe integrated process top layer metal 45 and is located within a metalcavity 48 formed by stacking intermediate layer metals, other than theintegrated process top layer metal 45 and an integrated process bottomlayer metal 49 in an integrated process, and metal vias.

Preferably, the on-chip H-shaped slot structures 41, 42, 43 and 44 ofthe present embodiment are designed and processed using a silicon-basedprocess so as to excite the rectangular dielectric resonator block 47overlying it and optimize the impedance matching effect. In addition,the insulating adhesive layer 46 has good thermal stability for fixingthe rectangular dielectric resonator block 47 to a surface of theon-chip excitation structure.

More preferably, the rectangular dielectric resonator block of thepresent embodiment has a larger relative dielectric constant, forexample, a relative dielectric constant of >5, so that the insulatingmaterial is processed into a specific size to couple and radiate anelectromagnetic field to the space. In addition, the rectangulardielectric resonance mode of the present embodiment is a TE_(1,δ,3)mode.

In this embodiment, the center frequency of the 2×2 on-chip dielectricresonant terahertz antenna array 4 is 300 GHz, and magnesium oxidehaving a relative dielectric constant of 9.65 is selected as thematerial of the rectangular dielectric resonator block 47. A parameter(Towerjazz SBC18H3) of the 0.18mGeSi BiCMOS process is selected todesign the on-chip structure, and there are six layers of metalMetal1-Metal6 and five layers of metal vias Via1-Via5 in this process.

Referring to FIG. 1, the matching network 5 of the present embodimentcomprises a first transmission line 51, of which two ports are connectedto a 2×2 on-chip dielectric resonant terahertz antenna array 4 and asource, respectively. The middle portion of the first transmission line51 is connected to an end of a second transmission line 52, and theother end of the second transmission line 52 is grounded. The matchingnetwork 5 is composed of two microstrip transmission lines, the firsttransmission line 51 and the second transmission line 52. The matchingnetwork 5 is mainly used to improve the power transmission efficiencybetween the antenna and the transistor, and a DC power supply isprovided for the source 31 of the transistor. The left end of themicrostrip first transmission line 51 is connected to the 2×2 on-chipdielectric resonant terahertz antenna array 4, and the right end of themicrostrip first transmission line 51 is connected to the source 31 ofthe NMOSFET 3.

The gate 33 of the NMOSFET 3 of the present embodiment is loaded with afixed first bias voltage 1 and a first bias resistor 2, and an open-endquarter-wavelength third transmission line 53 is connected between thegate 33 of the NMOSFET and the first bias resistor 2. The open-endquarter-wavelength third transmission line 53 is mainly used toeliminate the influence of the gate DC bias on the impedance matchingbetween the antenna and the transistor.

In the present embodiment, a first DC blocking capacitor 6, a secondbias voltage 7, and a second bias resistor 8 are connected between thedrain 32 of the NMOSFET 3 and the forward input terminal of the lownoise preamplifier 9, wherein the second bias voltage 7 and the secondbias resistor 8 are used for supplying power to the low noisepreamplifier 9.

The voltage feedback loop of the present embodiment comprises a firstresistor 10 connected to two ends of the low noise preamplifier 9, aleft end of the first resistor 10 connected to a negative terminal ofthe low noise preamplifier 9 is sequentially connected to a secondresistor 11, a second DC blocking capacitor 12 and the ground, and aright end of the first resistor 10 is also sequentially connected to athird DC blocking capacitor 14 and the ground. The voltage feedback loopof the low noise preamplifier 9 is mainly composed of the first resistor10, the second resistor 11, the second DC blocking capacitor 12 and thethird DC blocking capacitor 14, wherein the gain of the low noisepreamplifier 9 can be adjusted by changing the resistance values of thefirst resistor 10 and the second resistor 11.

Referring to FIG. 6 to FIG. 11, the design of the 2×2 on-chip dielectricresonant terahertz antenna array 4 specifically comprises the followingdesign steps.

1. Design of rectangular dielectric resonator block. The resonant modeis in TE_(m,δ,n) mode, and the dimensions of the rectangular dielectricresonator block as shown in FIG. 6 can be calculated by solving thetranscendental equation (1):

$\begin{matrix}{\mspace{76mu}{{k_{y}\mspace{14mu}{\tan\left( \frac{k_{y}W_{DRA}}{2} \right)}} = \sqrt{{\left( {ɛ_{r} - 1} \right)k_{mn}^{2}} - k_{y}^{2}}}} & (1) \\{{k_{mn} = \frac{2\pi\; f_{mn}}{c}},{k_{x} = {m\frac{\pi}{L_{DRA}}}},{k_{z} = {n\frac{\pi}{2H_{DRA}}}},{{k_{x}^{2} + k_{y}^{2} + k_{z}^{2}} = {ɛ_{r}k_{mn}^{2}}}} & (2)\end{matrix}$where Equations (2) is the explanation for parameters of the equation(1), wherein c is the speed of light, and f_(mn), is the operatingfrequency of the rectangular dielectric resonator block in this mode.The TE_(1,δ,3) mode of high-order resonant modes is selected as theresonant mode of the rectangular dielectric resonator block in theembodiment of the present disclosure, and has a higher gain than thebase mode. The transcendental equation (1) is solved by programming withthe mathematical software Matlab, obtaining the dimensions of therectangular dielectric resonator block at 300 GHz as: W_(DR)=250 μm,L_(DR)=250 μm, H_(DR)=400 μm.

2. Design of on-chip excitation structure. The on-chip H-shaped slotstructure is shown in FIG. 4. In the design process, the top layer metalMetal6 is selected to design the slot structure, while the bottom layermetal Metal1 is selected as the metal base plate to suppress theelectromagnetic wave from propagating toward a high-loss siliconsubstrate, and the intermediate metal layer and metal vias are stackedto form a metal shield cavity around the H-shaped slot structure, tosuppress electromagnetic leakage and reduce loss.

The dimension parameters of the H-shaped slot structure are:

I₁=70 μm, I₂=220 μm, w_(s)=9.5 μm, w₁=15 μm, w₂=10 μm, w₃=10 μm

3. Selection of the insulating adhesive layer 42. The insulatingadhesive layer 42 is made of a thermally stable insulating adhesivehaving a relative dielectric constant of 2.4 and a thickness of 10 μm,for bonding the rectangular dielectric resonator block 43 and theon-chip H-shaped slot structure 41.

4. Design of a 4-way GCPW power division network. A GCPW transmissionline structure composed of the top layer metal Metal6 and the bottomlayer metal Metal1 is adopted to design a 4-way power division network,and then parameters is optimized by means of HFSS software so as to meetimpedance matching and port phase requirements of the GCPW powerdivision network. FIG. 7 is a graph showing the S-parameter of the 4-wayGCPW sub-network as a function of frequency. FIG. 8 is a graph showingthe phases between the ports of the 4-way GCPW sub-network as a functionof frequency.

5. Performing co-simulation and optimization of the 4-way GCPW powerdivision network with the 2×2 on-chip dielectric resonant terahertzantenna array. The return loss S11 and the gain of the 2×2 on-chipdielectric resonant terahertz antenna array obtained by co-simulation asa function of frequency are shown in FIG. 9 and FIG. 10, respectively,where the impedance matching bandwidth of the 2×2 on-chip dielectricresonant terahertz antenna array at −10 dB is 20.1% (268-328 GHz), thepeak gain of the on-chip dielectric resonant terahertz antenna is 9.91dBi and the gain bandwidth at 3 dB is 16% (266-314 GHz). The radiationpattern of the 2×2 on-chip dielectric resonant terahertz antenna arrayis shown in FIG. 11, which has a narrower lobe width and betterdirectivity, and its radiation efficiency is as high as 51%.

Therefore, the output voltage signal of the NMOSFET terahertz detectorbased on the 2×2 on-chip dielectric resonant terahertz antenna arrayaccording to the embodiment of the present disclosure is a DC voltagesignal, and the magnitude of the DC voltage signal is proportional tothe radiation intensity of the terahertz signal. The intensityinformation of the incident terahertz signal can be obtained accordingto the magnitude of the output voltage signal of the terahertz detector,thereby realizing terahertz detection.

The above is only a preferred embodiment of the present disclosure,which is not intended to limit the scope of the disclosure. Allequivalent structural alterations made by using the disclosure of thepresent specification and drawings, or directly or indirectly utilizedin other related technical fields, in the concept of the presentdisclosure, are encompassed within the scope of patent protection of thepresent disclosure.

What is claimed is:
 1. A terahertz detector based on a N×M dielectricresonant antenna array, comprising a N×M on-chip dielectric resonantterahertz antenna array, wherein the N is the number of rows in thearray, the M is the number of columns in the array and the N and the Mare positive integers, wherein the N×M on-chip dielectric resonantterahertz antenna array is connected to a matching network, the matchingnetwork is connected to a source of a N-type Metal-Oxide-SemiconductorField-Effect Transistor (NMOSFET), a gate of the NMOSFET is sequentiallyconnected to a first bias resistor and a first bias voltage, a thirdtransmission line is connected between the first bias resistor and thegate, a drain of the NMOSFET is connected to a first Direct Current (DC)blocking capacitor, the other end of the first DC blocking capacitor isconnected to a low noise preamplifier, a second bias resistor and asecond bias voltage are further connected between the first DC blockingcapacitor and the low noise preamplifier, and the low noise preamplifieris further provided with a voltage feedback loop.
 2. The terahertzdetector of claim 1, wherein the N×M on-chip dielectric resonantterahertz antenna array is an array structure consisting of N×M on-chipH-shaped slot structures, each of the on-chip H-shaped slot structuresis connected at the surface with a rectangular dielectric resonatorblock through an insulating adhesive layer, and a connection slotextending outwardly of each of the on-chip H-shaped slot structures issequentially connected to the connection slots of adjacent on-chipH-shaped slot structures and form a non-overlapping power divisionnetwork ring, the power division network ring being provided with twoparallel antenna-sections connected to the outside.
 3. The terahertzdetector of claim 2, wherein when both the N and the M are even, aconnection port of the connection slot of the uppermost on-chip H-shapedslot structure and a connection port of the connection slot of thelowermost on-chip H-shaped slot structure have a phase difference of180°.
 4. The terahertz detector of claim 3, wherein the on-chip H-shapedslot structures are formed on a surface of an integrated process toplayer metal and is located within a metal cavity formed by stackingintermediate layer metals, other than the integrated process top layermetal and an integrated process bottom layer metal in an integratedprocess, and metal vias.
 5. The terahertz detector of claim 4, whereinthe on-chip H-shaped slot structure comprises a left vertical slot and aright vertical slot arranged in parallel, opposite sides of the leftvertical slot and the right vertical slot are connected to an invertedL-shaped left side slot and right side slot, respectively, a horizontalportion of the left side slot is connected in the middle of the leftvertical slot, a horizontal portion of the right side slot is connectedin the middle of the right vertical slot, and vertical portions of theleft side slot and the right side slot are parallel to each other andconstitute two lead-out slots for connecting the antenna to an outsidestructure.
 6. The terahertz detector of claim 1, wherein the matchingnetwork comprises a first transmission line connected to the on-chipdielectric resonant terahertz antenna and the source respectively atboth ends, a middle portion of the first transmission line is connectedto one end of a second transmission line, and the other end of thesecond transmission line is grounded.
 7. The terahertz detector of claim1, wherein the voltage feedback loop comprises a first resistorconnected to two ends of the low noise preamplifier, a left end of thefirst resistor connected to a negative terminal of the low noisepreamplifier is sequentially connected to a second resistor, a second DCblocking capacitor and the ground, and a right end of the first resistoris also sequentially connected to a third DC blocking capacitor and theground.
 8. A method of designing an N×M on-chip dielectric resonantterahertz antenna array, wherein the N is the number of rows in thearray, the M is the number of columns in the array and the N and the Mare positive integers, comprising: S1: with a resonance mode being inTE_(m,δ,n) mode, calculating 3D dimensions of the rectangular dielectricresonator block by solving a transcendental equation, the transcendentalequation being:${k_{y}\mspace{14mu}{\tan\left( \frac{k_{y}W_{DRA}}{2} \right)}} = \sqrt{{\left( {ɛ_{r} - 1} \right)k_{mn}^{2}} - k_{y}^{2}}$wherein${k_{mn} = \frac{2\pi\; f_{mn}}{c}},{k_{x} = {m\frac{\pi}{L_{DRA}}}},{k_{z} = {n\frac{\pi}{2H_{DRA}}}},{{k_{x}^{2} + k_{y}^{2} + k_{z}^{2}} = {ɛ_{r}k_{mn}^{2}}},$c is the speed of light, ε_(r) is a relative dielectric constant andf_(mn) is the operating frequency of the rectangular dielectricresonator block in said mode TE_(m,δ,n); wherein m, n and δ are thenumber of electromagnetic waves generated in the x, y, z directions, andare integers; wherein k_(y) is the component of the propagation constantof electromagnetic waves in the medium in the y direction, and k_(mn) isthe propagation constant of electromagnetic waves in the medium, whereink_(x) and k_(z) are the components of the propagation constant in the xand z directions when electromagnetic waves propagate in the medium;wherein W_(DRA) is the width of the medium in the x direction, L_(DRA)is the length of the medium in the y direction, and H_(DRA) is theheight of the medium in the z direction; S2: in a process of designingan on-chip excitation structure, selecting a top layer metal Metal6 todesign a H-shaped slot structure while selecting a bottom layer metalMetal1 as a metal base plate, and stacking intermediate metal layers andmetal vias to form a metal shielding cavity around the H-shaped slotstructure; S3: selecting a suitable insulating adhesive layer to combinethe rectangular dielectric resonator block and the on-chip H-shaped slotstructure; S4: adopting a Grounded Coplanar Waveguide (GCPW)transmission line structure composed of the top layer metal Metal6 andthe bottom layer metal Metal1 to design a power division network, andthen optimizing parameters by means of High Frequency StructureSimulator (HFSS) software so as to meet impedance matching and portphase requirements of the GCPW power division network; and S5:performing co-simulation and optimization of the GCPW power divisionnetwork with the N×M on-chip dielectric resonant terahertz antennaarray.
 9. The method of claim 8, wherein in the S1, the resonance modeof the rectangular dielectric resonator block is selected to beTE_(m,δ,n) mode of high-order resonant modes, and the transcendentalequation is solved by programming with mathematical software Matlab, toobtain the 3D dimensions of the rectangular dielectric resonator blockat a frequency of 300 GHz being W_(DR)=250 μm, L_(DR)=250 μm, H_(DR)=400μm, respectively; in the S2, the dimensions of the H-shaped slotstructure are I₁=70 μm, I₂=220 μm, w_(s)=9.5 μm, w₁=15 μm, w₂=10 μm,w₃=10 μm; and the insulating adhesive layer mentioned in the step S3 isselected as a thermal stability insulating adhesive having a relativedielectric constant ε_(r) of 2.4 and a thickness of 10 μm.